1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // UNSUPPORTED: libcpp-has-no-threads
11 // UNSUPPORTED: c++03, c++98, c++11
12 
13 // <shared_mutex>
14 
15 // class shared_timed_mutex;
16 
17 // void lock_shared();
18 
19 #include <shared_mutex>
20 #include <thread>
21 #include <vector>
22 #include <cstdlib>
23 #include <cassert>
24 
25 std::shared_timed_mutex m;
26 
27 typedef std::chrono::system_clock Clock;
28 typedef Clock::time_point time_point;
29 typedef Clock::duration duration;
30 typedef std::chrono::milliseconds ms;
31 typedef std::chrono::nanoseconds ns;
32 
f()33 void f()
34 {
35     time_point t0 = Clock::now();
36     m.lock_shared();
37     time_point t1 = Clock::now();
38     m.unlock_shared();
39     ns d = t1 - t0 - ms(250);
40     assert(d < ms(50));  // within 50ms
41 }
42 
g()43 void g()
44 {
45     time_point t0 = Clock::now();
46     m.lock_shared();
47     time_point t1 = Clock::now();
48     m.unlock_shared();
49     ns d = t1 - t0;
50     assert(d < ms(50));  // within 50ms
51 }
52 
53 
main()54 int main()
55 {
56     m.lock();
57     std::vector<std::thread> v;
58     for (int i = 0; i < 5; ++i)
59         v.push_back(std::thread(f));
60     std::this_thread::sleep_for(ms(250));
61     m.unlock();
62     for (auto& t : v)
63         t.join();
64     m.lock_shared();
65     for (auto& t : v)
66         t = std::thread(g);
67     std::thread q(f);
68     std::this_thread::sleep_for(ms(250));
69     m.unlock_shared();
70     for (auto& t : v)
71         t.join();
72     q.join();
73 }
74